Rub the head of your penis calmly enough so you don't have the urge to contract the muscle that spasms during orgasm. Remain completely relaxed, and release all tension in your muscles, breathing, and anywhere else in your body. Free your mind, and don't dwell on the pleasure or the hardness of your penis. Even when you feel like orgasming, remain relaxed and release the pleasure. Breathe normally. You will continue to build the intense feeling until you reach a point where you simply can't stand it anymore. If you are skillful, you may even experience a kind of momentary blindness. Even when you feel like exploding, stay relaxed, enjoy the intense pleasure, and keep rubbing!